[EPAC-1979]: apply adaptive reading width to long-form lists

[riddim-developer-bot]

Reviewer-Boundary: review-only

Resolves EPAC-1979

Why

Long-form reading surfaces in the iPad/macOS layout were still stretching across regular-width panes after the adaptive layout primitives landed. This applies the existing 720pt adaptiveReadingWidth cap where the app presents Hansard chat, feed cards, petitions, search result bodies, bill/expenditure details, and member profile/voting content.

What changed

• Added .adaptiveReadingWidth() to the named long-form List containers in Bills, Expenditures, Home, Petitions, and member voting views.
• Wrapped the MemberProfileView scroll content in an inner container and applied the modifier there, preserving the ScrollView itself.
• Applied the cap only to Search votes, bills, and debates sections so member result rows remain full-width.
• Recorded the EPAC-1979 visual QA gate on EPAC-1980 (human handoff).

Trade-offs not taken

• Did not apply the modifier to tabular root lists such as Members, Bills, or Expenditures list screens; those are not long-form reading surfaces.
• Did not fold unrelated SwiftLint baseline cleanup or snapshot refreshes into this layout PR.

Test plan

• PASS: python3 scripts/localization/check_localizations.py --github-warnings
• PASS: cd ios && make build
• PASS: git diff --check origin/main...HEAD
• PARTIAL: cd ios && make test built and ran tests, and AdaptiveLayoutTests plus the later smoke UI tests passed. The full target exited Error 65 from existing failures: snapshot mismatches in SnapshotTests (DataSourceBadge_*, PartyBadge_allParties, Settings_root), broad non-layout unit failures reported after the first failed run, and OnboardingAndFirstDebateUITests.test_freshInstall_dismissesOnboarding_opensFirstDebate with Application net.dinglebox.cabinetdoor is not running.
• FAILING BASELINE: cd ios && swiftlint --strict reports 1010 existing repository-wide violations. A changed-file lint pass also reports pre-existing style violations in touched files; the new modifier lines do not introduce syntax/build issues.

Screenshots

Not attached from this run. Local build verification passed, but the full test/visual automation path is currently blocked by the unrelated baseline failures listed above. EPAC-1980 now contains the required human iPad landscape Hansard chat visual-QA item.

Release-Note: Improves iPad and Mac readability by keeping long-form civic content at a comfortable reading width.